March 19, 2012
Los Angeles, like many cities, grew along the banks of its water source (History of the Los Angeles River). After some time, the Los Angeles River proved to be a liability to Angelinos because of its extreme flooding. After a particularly vicious flood 1914, and another one in 1934. The Federal Congress passed the Flood Control Act, which allowed the U.S. Army Corps of Engineers curb the 52 mile river by building dams and channelizing all but 10 percent of it.
The concrete paving and straightening of the river increased the speed of the river’s flow by reducing friction between water and its channel, and by reducing the distance the water would have to travel before exiting the watershed by means of ocean. The new cement walls and bottom that lined the River ensured that the city was protected from floods but it also completely changed the river into a “concrete coffin.” (History of the Los Angeles River)
The L.A. River’s unique flora and fauna benefited the least from the development, as their habitat was completely wiped out. Before the dramatic growth and urbanization of Los Angeles, the River and its banks provided unique habitat for many plant and animal species. Flora included sycamore, alder, cottonwood and oak trees, as well as elderberry, cattail, and mugwort plants. Fauna included the now endangered yellow-billed cuckoo, steelhead trout, Pacific lamprey eel, Pacific brook lamprey eel, Santa Ana sucker, and many more species. Revitalization efforts of the river have resulted in stocking the river with non-native species for fishing, and non-native species are known to have negative effects on native ecosystems. There have also been major encroachments of non-native plant species like fennel, mustard, palm, and cocklebur. (Education…FoLAR).
The concrete paving of waterways in essence, replaces vegetative cover with impervious concrete. It lowers the capacity for absorption and infiltration of the precipitated water because de-vegetation reduces the organic matter content of the ground and replaces it with surfaces that are water cannot permeate well through, like cement (Wilson “Floods”). Vegetation is essentially a buffer between precipitation and flooding, and its deficit increases flood frequency and magnitude.
A solution for improvements to the L.A. River fit under the category of revitalization efforts. Various conservation groups advocate distinct methods to achieve revitalization, though the general trend is to reduce the presence of the “concrete coffin” and increase the amount of recreational space alongside the banks of the river. It would be best to advocate the restoration of riparian habitats and the cultivating of native species that were traditionally present. These native species would most likely work the best due to their natural temperature and climate, as well as have the least amount of negative effects on other native species. Many also recommend the building of compact mixed-use developments and parks alongside the banks of the river in order to create a kind of civic space. (“Guide to the Los Angeles River- Revitalization.”)
“HISTORY OF THE LOS ANGELES RIVER.” Dpw.lacounty.gov. Los Angeles Department of Public Works. Web. 15 Nov. 2011. <http://ladpw.org/wmd/watershed/LA/History.cfm>.
“Birds, Plants, Fish.” Friends of the Los Angeles River (FoLAR). (FoLAR). Web. 1 Nov. 2011. <http://folar.org/?page_id=8>.
“Guide to the Los Angeles River- Revitalization.” Http://thelariver.com. Los Angeles River Revitalization Corporation. Web. 1 Nov. 2011. <http://thelariver.com/about/>.
Sarah Beshir and Ashley Lukashevsky are undergraduates in the USC Dana and David Dornsife College of Letters, Arts and Sciences.